Nine Allied nations signed Japan's formal surrender instrument on USS Missouri in 1945.
The signatories represented the United States, China, the United Kingdom, the Soviet Union, Australia, Canada, France, the Netherlands, and New Zealand. Douglas MacArthur signed first for the Allied powers, followed by Fleet Admiral Chester Nimitz as the U.S. representative.
The Japanese side had two principal signatories: Foreign Minister Mamoru Shigemitsu signed for the Japanese government, and General Yoshijiro Umezu signed for Imperial General Headquarters. The document therefore recorded both Japanese authority and the governments of the Allied coalition.
The nine-nation count refers to the Allied governments whose representatives signed the instrument. It does not count every country that fought Japan or every vessel present in Tokyo Bay, since the surrounding fleet included ships from additional supporting forces.